Substrate support structure, clamp preparation unit, and lithography system

Abstract

A substrate support structure for clamping a substrate on a surface by means of a capillary layer of a liquid. The surface has an outer edge and includes one or more substrate supporting elements for receiving the substrate to be clamped, wherein the one or more substrate supporting elements are arranged to provide support for the substrate at a plurality of support locations. The substrate support structure further includes a sealing structure circumscribing the surface and having a top surface or edge forming a sealing rim. A distance between the outer edge of the surface and an outermost of the support locations is greater than a distance between the outer edge and the sealing rim.

The invention claimed is: 
     
       1. A substrate support structure for clamping a substrate on a surface of the substrate support structure by means of a capillary layer of a liquid having an outer liquid surface, the surface of the substrate support structure having an outer edge and comprising one or more substrate supporting elements for receiving the substrate to be clamped,
 wherein the one or more substrate supporting elements are arranged to provide support for the substrate at a plurality of support locations, 
 wherein the substrate support structure further comprises a sealing structure circumscribing the surface of the substrate support structure for substantially closing off a circumferential opening facing the outer liquid surface and having a top surface or edge forming a sealing rim, 
 wherein a distance between the outer edge of the surface of the substrate support structure and an outermost one of the support locations is greater than a distance between the outer edge and the sealing rim, and 
 wherein a distance between the sealing rim and the outermost support location is greater than a maximum distance between adjacent support locations; and 
 wherein the sealing rim is substantially level with a top of the substrate supporting elements. 
 
     
     
       2. The substrate support structure of  claim 1 , wherein the distance between the outer edge of the surface of the substrate support structure and the outermost support location is greater than or equal to twice the distance between the outer edge and the sealing rim. 
     
     
       3. The substrate support structure of  claim 1 , wherein the distance between the sealing rim and the outermost support location is greater than or equal to twice the maximum distance between adjacent support locations. 
     
     
       4. The substrate support structure of  claim 1 , wherein the distance between the outer edge of the surface of the substrate support structure and the outermost support location is greater than or equal to twice the maximum distance between adjacent support locations. 
     
     
       5. The substrate support structure of  claim 1 , wherein the distance between the outer edge of the surface of the substrate support structure and the outermost support location is equal to or larger than a nominal distance between said supporting locations, and wherein the distance between the outer edge and the sealing rim is equal to or smaller than said nominal distance. 
     
     
       6. The substrate support structure of  claim 1 , wherein the one or more substrate supporting elements provide support for the substrate at a plurality of said support locations arranged in a regular pattern with a mutual pitch, and the distance between the sealing rim and the support locations nearest to the sealing rim exceeds said pitch. 
     
     
       7. The substrate support structure of  claim 1 , wherein the surface of the substrate support structure further comprises portions with different capillary potential for inducing, during clamping, a predetermined capillary flow within the liquid capillary layer. 
     
     
       8. The substrate support structure of  claim 1 , wherein a moat is provided around the surface, the moat comprising a higher stepped portion at the perimeter of the surface. 
     
     
       9. The substrate support structure of  claim 8 , wherein a height difference between a top surface of the substrate supporting elements and the stepped portion of the moat is greater than or equal to twice the height of the substrate supporting elements. 
     
     
       10. The substrate support structure of  claim 1 , wherein the surface of the substrate support structure is provided with elevated structures for forming a plurality of compartments. 
     
     
       11. The substrate support structure of  claim 1 , further comprising a liquid removal system for removing liquid circumferential to said surface. 
     
     
       12. A substrate support structure for clamping a substrate on a surface of the substrate support structure by means of a capillary layer of a liquid having an outer liquid surface, the surface of the substrate support structure having an outer edge and comprising one or more substrate supporting elements for receiving the substrate to be clamped,
 wherein the one or more substrate supporting elements are arranged to provide support for the substrate at a plurality of support locations, 
 wherein the substrate support structure further comprises a sealing structure circumscribing the surface of the substrate support structure for substantially closing off a circumferential opening facing the outer liquid surface and having a top surface or edge forming a sealing rim, and 
 wherein a distance between the outer edge of the surface of the substrate support structure and an outermost support location is equal to or larger than a nominal distance between said supporting locations, and wherein a distance between the outer edge and the sealing rim is equal to or smaller than said nominal distance. 
 
     
     
       13. The substrate support structure of  claim 12 , wherein the one or more substrate supporting elements provide support for the substrate at a plurality of support locations arranged in a regular pattern with a mutual pitch, and a distance between the sealing rim and the support locations nearest to the sealing rim exceeds said pitch. 
     
     
       14. The substrate support structure of  claim 12 , wherein the sealing rim is substantially level with a top of the substrate supporting elements. 
     
     
       15. The substrate support structure of  claim 12 , wherein the surface of the substrate support structure further comprises portions with different capillary potential for inducing, during clamping, a predetermined capillary flow within the liquid capillary layer. 
     
     
       16. A combination of a substrate support structure and a substrate clamped on a surface of the substrate support structure by means of a capillary layer of a liquid having an outer liquid surface, the surface of the substrate support structure comprising one or more substrate supporting elements for receiving the substrate and arranged to provide support for the substrate at one or more support locations,
 wherein the substrate support structure further comprises a sealing structure around the surface of the substrate support structure for substantially closing off a circumferential opening facing the outer liquid surface and having a top surface or edge forming a sealing rim, and 
 wherein a distance between the sealing rim and an outermost one of the support locations is greater than a maximum distance between adjacent support locations. 
 
     
     
       17. The combination of  claim 16 , wherein, during clamping of the substrate, the substrate bends downwards to reduce a gap between the sealing rim and a bottom surface of the substrate so that the bottom surface of the substrate touches the sealing rim. 
     
     
       18. The combination of  claim 16 , wherein the distance between the sealing rim and the outermost support location is greater than or equal to twice the maximum distance between adjacent support locations. 
     
     
       19. The combination of  claim 16 , wherein the distance between the outer liquid surface of the capillary liquid layer and the outermost support location is greater than the distance between the outer liquid surface of the capillary liquid layer and the sealing rim. 
     
     
       20. The combination of  claim 16 , wherein the surface of the substrate support structure further comprises portions with different capillary potential for inducing, during clamping, a predetermined capillary flow within the liquid capillary layer. 
     
     
       21. The combination of  claim 20 , wherein the predetermined capillary flow within the liquid clamping layer is in a direction towards the outer liquid surface of the liquid clamping layer.